/Engine/Plugins/Experimental/CharacterFXEditor/BaseCharacterFXEditor/Source/BaseCharacterFXEditor/Public/BaseCharacterFXEditor.h
However, since we're using a mode and the Interactive Tools Framework, a lot of our business logic ends up inside the mode and the tools, not the subsystem. The front-facing code is mostly in the asset editor toolkit, though the mode toolkit has most of the things that deal with the toolbar on the left.
[UCLASS](Programming/UnrealArchitecture/Reference/Classes#classdeclaration)(Abstract) class UBaseCharacterFXEditor : public [UAssetEditor](API\Editor\UnrealEd\Tools\UAssetEditor)
TArray<TObject...
OriginalObjectsToEdit
Note that things like CloseWindow, FocusWindow, and IsPrimaryEditor seem to be called on the toolkit, not the editor class, so they are overriden there.